This post is posted by Salman of Best Tips Blogging
Here are some common but important concepts which you could be asked to explain.
a) OOP: Object Oriented Programming is a programming model that relies on representing real world objects in your code. Using analogies with reality then makes it easier for you to design your program. There's obviously a lot more to this, so make sure you read up before wantonly dropping it into an interview. In general, praise it, for it is good.
b) SDLC: The Software Development Life Cycle is a bunch of procedures and documents that take a software project from a neat idea to a saleable product. There's the analysis, planning, design, coding, testing and finally the maintenence of the product. A sufficiently vague statement would be,"I think current SDLc models are long overdue for a revamp."
c) Garbage collector: A feature of Java an the .Net frameworks, the garbage collector is a process that cleans the system's memory of objects and variables that programs aren't using. So if you're asked how you're going to go about cleaning the memory in, say, C#, it's a trick question-you dont really need to-the garbage collector does it.
d) Classifieds: A novel concept, and what you'll need if you really try to bluff your way through a technical interview :D